1. Field of the Invention
The present invention relates to an unlocking mechanism provided in a reclining device for allowing a seat back of seat to be adjustably inclined. In particular, the invention is directed to the unlocking mechanism of this kind which is remotely operable by a lever disposed on an upper portion of the seat back.
2. Description of Prior Art
There has been made available various kinds of reclinable seats for vehicles, each of which is normally provided with a reclining device for allowing a seat back thereof to be adjustably inclined.
Irrespective of such reclining action, it is frequently necessary to incline the seat back to a desired position or to fold down the seat back onto a seat cushion into a full flat state, and, in some cases, it is necessary to displace a seat back of front seat forwardly to a so-called “walk-in” position which allows a passenger to climb onto or descend from a rear seat without interference with the front seat. For that purpose, as typically disclosed from the Japanese Laid-Open Patent Publication No. 2005-52170, a remotely controllable type of unlocking mechanism is provided in the top area of seat back to allow for releasing the seat back from a locked state caused by the reclining device, and further, an angular change mechanism is provided between that particular unlocking mechanism and a driving shaft of the reclining device.
In brief, according to the foregoing Japanese publication, an unlocking lever is provided in the top area of seat back, from which a sheathed wire cable extends to the reclining device, as a transmission means, so that an operation by the unlocking lever will be transmitted through the wire cable to the reclining device, to thereby unlock the seat back from the reclining device. In this prior art, three bevel gears, arm and spring are operatively connected between the wire cable and the driving shaft of reclining device, as an angular adjustment mechanism for causing the seat back to incline adjustingly to a desired angle, independently of the reclining device.
However, such prior-art unlocking mechanism involves the following problems: i) the three bevel gears are meshed with one another in a three-dimensionally massive manner, which is not only quite complicated in structure, but also increases a whole size of the mechanism that may impair a cushion quality of padding potions adjacent to the bevel gears, and ii) the provision of three bevel gears and spring in the transmission system apparently causes a loss in transmission efficiency and therefore can not provide a sufficient and quick transmission of operation to the driving shaft of reclining device, as a result of which, it is impossible to attain a precise and quick responsive operationability for the remotely controlled unlocking action of the reclining device.